Evolution of air inlets showing the wide variety of configurations adopted over the years.

Su-37 Flanker-derivative with thrust vector control nozzles on its Lyulka-Saturn AL-37FU turbofans demonstrated a somersault manoeuvre at the 1996 Farnborough Airshow. The nozzles, currently made of steel, will be of titanium on production versions and operate 75° in pitch only at 30°/sec.

Ground testing of the P&W/Low Observable Axisymmetric Nozzle (LOAN) was completed recently on an F-16. The LOAN provides a significant reduction in radar cross section and IR signature emissions from the engine through geometrical shaping, an advanced cooling system and special coatings on internal and external structures. The nozzle has potential applications on the Lockheed Martin Joint Strike Fighter and the world’s fleet of F-16s.

The ability of an aircraft to supercruise will not only stretch combat radius but forces an adversary to expend his own fuel in order to get his aircraft to an energy state where he can engage. Both Lockheed Martin’s F-22 and Eurofighter’s EF2000 will be able to supercruise in the Mach 1.4-1.5 region. The F-22’s Pratt & Whitney F119 turbofan’s twin spools counter-rotate to reduce the gyroscopic moments set up in high angular rate manoeuvres. Illustrated here is one of the YF-22 prototypes.

As if intake designers did not have enough to cope with in providing smooth, distortion free air to the engine; the MiG-29 has intake guards deployed during taxiing, take-off and landing to protect the engine from foreign object damage. While the guards are in place, air is fed to the engine through grills in the upper wing root.

Proposed for the air-defence of the UK, the mixed-powerplant Saunders-Roe SR53 was powered by a de Havilland Spectre rocket engine operating on hydrogen peroxide and kerosene, controllable within the range 4.4-35.0kN. Endurance was provided by a 44kN thrust Armstrong Siddeley Viper lightweight turbojet. This and its SR177 descendant fell victim to the 1957 Defence White Paper.

Variation in air intake geometry of the F-15 obtainable by means of a moveable ramp (total movement of 15°) is clearly seen in this photograph taken during pre-flight checks. This four-shock intake gives optimum intake capture area throughout the Eagle’s flight envelope.